General Soil Information Soil Notes General Soil Information

Definition _______– relatively thin _______layer of the Earth’s ______ consisting of _______ and _____ matter that is affected by agents such as weather, wind, water, and organisms. ____________ Organisms, mainly microorganisms, inhabit the soil & depend on it for _______, ______ & ______. ______ anchor themselves into the soil, and get their ________ and ______. Terrestrial plants could not survive without soil, therefore, ______ could not _____ without soil either.

SOIL: A _____________ RESOURCE Soil is a slowly ______ resource that provides most of the ________ needed for plant growth and also helps purify water. Soil formation begins when bedrock is broken down by physical, chemical and biological processes called ___________. ________ soils, or soils that have developed over a long time are arranged in a series of horizontal layers called _____ _______.

Soil Formation Parent Material _____________ – 4 Distinct Parts The rock that has slowly broken down into smaller particles by __________,_________, and __________weathering. To form 2.5 cm (1 in.) it may take from _________ years. _____________ – 4 Distinct Parts ___________particles (45% of “typical” soil) _________matter (about 5%) _______(about 25%) _______ (about 25%)

____________ _______ Weather Ex. erosion (wind, water, ice, etc.) A plant’s roots or animal cells undergo cell respiration and the CO2 produced diffuses into soil, reacts with H2O & forms carbonic acid (H2CO3). This eats parts of the rock away.

Renewable or Not? ___________ produces new soil But, in the ________ rainforests, all of the nutrients are caught in the trees and when cut down & burned the soil _____ get the nutrients back.

Soil Properties: ________ The percentages (by weight) of different sized particles of ____, _____ and ____ that it contains. ____________ of soil depends on how soil particles are __________ and _________together (sand, silt, clay)

Texture (Cont.) >___mm in diameter = ________ (not actually considered soil because it doesn’t have direct _____ to plants. ________mm = ______ (the largest soil particles) can be seen easily with the eye. __________mm = ____ – about the size of flour and barely visible with the eye. <______mm = ______ (has the greatest surface value) – only seen under and electronic microscope.

_________ To tell the ____ in soil, take the soil, _____ it, and ___ it between your fingers and thumb. _______ -has a lot of sand ______- high clay content and you should be able to roll it into a clump _____- smooth, like flour. *What type of soil do you have? _____

How easily the soil can be ________. _________ _________ A measure of the _______ of soil and the average ________between the ________. How easily the soil can be ________.

____________ The ____ at which water and air moves from ______ to _____ soil layers. It is ______ between those spaces.

Some Soil _________ Soils _____ in the _____ of the particles they contain, the amount of _____ between these particles, and how rapidly _____ flows through them.

______-______ Potential Some soils, like ______, ____ when ____ gets in them, then they ____ and crack. This is ___ for house _________, etc.

_____ The pH of most soils ranges from ___ to _____. But, the soil of the _______ Forest in California is extremely _______ (2.8-3.9) and in _____ Valley, California, it is very _____ (10.5). _______ are affected by ____ because of the solubility of ________ minerals.

________ Steep slopes often have _____ or ___ soil on them because of ________. _____ from precipitation tends to _____ the slope also. ______ slopes and ____ may ______ the formation of deep ____.

______ Some soils are very _____ (like in some places in San Antonio). It can be only ____ inches of soil and then you hit _____. Other areas can have soil ___ inches deep or more.

______ ____ soil is rich with lots of ______ matter. ______ soil (like sand) is not so rich with very _____ organic matter.

Soil ________

_______ Layer (___-horizon) The ________ layer; it is ___ in organic material. Plant _____ accumulates in the O-horizon and _______decays. In _______ soils the O-horizon is completely ______, but in certain organically rich soils it may be the dominant layer.

________ (___-horizon) It is _____ and rich in accumulated organic _____ and ______. It has a _____ texture and is somewhat ________ due to the ____ of many nutrient minerals to deeper layers and by _______.

________ (___-horizon) The ______-colored subsoil beneath the A-horizon; it is often a zone of ________ where ______ minerals have _____ out of the topsoil and litter accumulate. It is typically ____ in _____ and ________ compounds and clay.

_______ Material (___-horizon) This contains _______ pieces of ____ and borders the ______ solid parent material. Most ______ do not go down this deep and it is often ______ with groundwater.

Wood sorrel Oak tree Organic debris builds up Lords and ladies Dog violet Rock fragments Grasses and small shrubs Earthworm Millipede Fern Moss and lichen Honey fungus O horizon Mole Leaf litter A horizon Topsoil B horizon Bedrock Subsoil Immature soil Regolith Young soil C horizon Figure 3.23 Natural capital: soil formation and generalized soil profile. Horizons, or layers, vary in number, composition, and thickness, depending on the type of soil. (Used by permission of Macmillan Publishing Company from Derek Elsom, Earth, New York: Macmillan, 1992. Copyright © 1992 by Marshall Editions Developments Limited) Pseudoscorpion Mite Parent material Nematode Root system Actinomycetes Red Earth Mite Fungus Mature soil Bacteria Springtail Fig. 12-A, p. 284

_______ in Mature Soils _________: the _______ movement of _____ through soil. _________: dissolving of _____ and organic matter in upper layers carrying them to lower layers. The soil _____ determines the _______ of _______ and ________.

Desert Soil (hot, dry climate) Grassland Soil semiarid climate) Mosaic of closely packed pebbles, boulders Weak humus-mineral mixture Alkaline, dark, and rich in humus Dry, brown to reddish-brown with variable accumulations of clay, calcium and carbonate, and soluble salts Figure 3.24 Natural capital: soil profiles of the principal soil types typically found in five types of terrestrial ecosystems. Clay, calcium compounds Desert Soil (hot, dry climate) Grassland Soil semiarid climate)

Tropical Rain Forest Soil (humid, tropical climate) Acidic light-colored humus Figure 3.24 Natural capital: soil profiles of the principal soil types typically found in five types of terrestrial ecosystems. Iron and aluminum compounds mixed with clay Tropical Rain Forest Soil (humid, tropical climate)

Deciduous Forest Soil (humid, mild climate) Forest litter leaf mold Humus-mineral mixture Light, grayish-brown, silt loam Figure 3.24 Natural capital: soil profiles of the principal soil types typically found in five types of terrestrial ecosystems. Dark brown firm clay Deciduous Forest Soil (humid, mild climate)

Coniferous Forest Soil Acid litter and humus Light-colored and acidic Figure 3.24 Natural capital: soil profiles of the principal soil types typically found in five types of terrestrial ecosystems. Humus and iron and aluminum compounds Coniferous Forest Soil (humid, cold climate)

Case Study: _________ Food Production in the United States Industrialized agriculture uses about ____ of all commercial ______ in the U.S. and food travels an average ______ kilometers from farm to plate.

_________ Agriculture: Low Input ___________ Many farmers in developing countries use ____-______ agriculture to grow a variety of crops on each plot of land (__________) through: __________ ________: planting several genetic varieties. ____________: two or more different crops grown at the same time in a plot. ___________: crops and trees are grown together. _________: different plants are planted together.

________ ________ is the movement of _____components, especially surface litter and topsoil, from one place to another. ______ billion tons of soils are eroded from the U.S. each year; this would fill 320 million average-sized dump trucks that, if parked end-to-end, would extend to the moon and ¾ of the way back!

__________ In undisturbed ecosystems, the _______ of plants help ________ the soil, and usually soil is not lost faster then it forms. But, _______, _______, _______, _________ by livestock, _________, deliberate ________ of _________ etc. destroy plant cover and leave soil vulnerable to erosion. This ______ in a few _______ what nature took ________ to _________of years to produce.

SOIL ________ AND ___________ Soil erosion lowers soil ______ and can overload nearby bodies of ______ with eroded ________. ______ erosion: surface water or wind peel off thin layers of soil. _____ erosion: fast-flowing little rivulets of surface water make small channels. ______ erosion: fast-flowing water join together to cut wider and deeper ditches or gullies.

SOIL ________ AND __________ Soil erosion is the movement of soil components, especially surface litter and topsoil, by ____ or ______. Soil erosion increases through activities such as farming, logging, construction, overgrazing, and off-road vehicles. Figure 12-12

Global Outlook: Soil Erosion Soil is eroding _______ than it is forming on more than ________ of the world’s __________. Fig. 12-16, p. 289

Case Study: Soil Erosion in the ____ – Some Hopeful Signs Soil erodes faster than it forms on most U.S. cropland, but since _____, has been cut by about _____. 1985 _____ _______ _____ (Farm Act): farmers receive a _____ for taking highly erodible land out of _______ and replanting it with soil saving plants for _______ years.

Water Erosion _______ – water hits the soil at a ______ angle (based on _____) This can erode soil. _____ – when surface water moves down a _____ or across a _____ in a wide flow and peels off fairly uniform sheets of soil. Because the topsoil disappears _____, sheet erosion may ____ be _______ until too much _______ has been done.

Water Erosion (Cont.) _______ Slippage – (like in California) where it is very _____ and large amounts of _____ slip away in large _____ (_____ slides). _____ – concentrated flow across the surface of soil. Leaves ______ (micro channels).

_______ – rivulets of fast-flowing water join together and, with each succeeding rain, ____ the _______ wider and deeper until they become ______ or ______. Gully erosion usually happens on ____ ______ where all or most vegetation has been removed.

_______ Erosion ______ – one particle hitting another and being blown across the surface of the soil.

_________ – airborne soil. Ex _________ – airborne soil. Ex. soil from Lubbock is found in Temple, Texas.

______ Creep – _________ dunes; surface creeping slowly across ______ Creep – _________ dunes; surface creeping slowly across. __________ are an example of a very fast surface creep.

Desertification: Degrading Drylands __________ of world’s land has lost some of its productivity because of ________ and human _________ that reduce or degrade topsoil. Human agriculture accelerates _____________ Dust bowl in U.S. due to severe wind erosion of topsoil

We Can Reduce Desertification ___________________ Decrease: Population growth Overgrazing Deforestation Destructive forms of planting, irrigation, and mining Both _______ and ________ going through Desertification

_________ and _________ Repeated -________ can reduce crop yields by causing _____ buildup in the soil and waterlogging of crop plants.

___________ Irrigation Has Serious ______________ Soil ______________ Gradual ____________of _______ in the soil from irrigation water ________ crop yields and can even kill plants Affects _____% of world croplands _____________ Irrigation water gradually ________water table Can prevent roots from getting __________ Affects ____% of world croplands

Solutions Soil Salinization Prevention Cleanup Reduce irrigation Flush soil (expensive and wastes water) Use more efficient irrigation methods Stop growing crops for 2–5 years Figure 13.15 Solutions: methods for preventing and cleaning up soil salinization. QUESTION: Which two of these solutions do you think are the most important? Switch to salt-tolerant crops (such as barley, cotton, sugarbeet) Install underground drainage systems (expensive) Fig. 12-29, p. 307

Salinization and Waterlogging of Soils: A ________ of Irrigation Example of ____ _________, poor drainage, and severe _________. White _______ salts have _______ crops. Figure 12-17

Many Farmers Are Reducing Soil Erosion Terracing Contour planting Strip cropping with cover crop Alley cropping, agroforestry Windbreaks or shelterbelts Conservation-tillage farming Identify _________ hotspots

Erosion _______ _________ – can reduce _______ erosion. Long rows of ______ are planted to partially _____ the ____. They can also help ____ soil _______, supply some _____ for fuel, and provide _____ for birds.

______________ AGRICULTURE THROUGH SOIL CONSERVATION Modern farm __________ can plant crops without disturbing _______ (no-till and minimum tillage. _____________tillage farming: Increases ________ yield. Raises soil __________ content. _________ water use. Lowers __________. Uses less tractor ________.

________ Tillage – (conservation tillage) to disturb the soil as little as possible while planting crops. ______ tillers break ___and _____ the _______ soil _____ turning over the _______, previous crop residues, and any cover vegetation.

SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATION ________, _______ planting, ____ cropping, _____ cropping, and ________ can reduce soil erosion. Figure 12-26

________ Farming –sloping your growing crops, etc. _________ are run ______ parallel to the ground to stop soil from running down a steep slope. Plowing and planting crops in _____ across, rather than up and down, the sloped contour of the land.

_______ – (what you use for contour farming _______ – (what you use for contour farming.) Dirt goes up to hold the dirt in place. Broad, nearly ______ terraces that run across the land contour. Helps to retain ______ for crops at each level and _____ soil ______ by controlling ______.

_______ Cropping (________ cropping) – several crops are planted together in strips or alleys between trees and shrubs that can provide shade (which reduces water loss by evaporation) and helps to retain and slowly release soil moisture. ______ Cropping- a row crop such as corn alternates in strips with another crop that completely covers the soil, reducing erosion. catches and reduces water runoff and helps prevent the spread of pests and plant diseases.

Irrigation __________ Conventional __________ irrigation- allows _____of the water input to reach crops _______-flow irrigation- Valves that send water down irrigation ditches. _____ irrigation- Can raise water efficiency to ______and reduce water use by _____. ________ irrigation- allowing the natural floods to irrigate the crops. _____ in flood zones tend to be nutrient _____ and ______.

Soil __________ ______________ ___________ are ______ in atomic structure. Ex. ______, _________ & _________. ____________ These are ______ in atomic structure. Plants need them in _____ amounts. Ex. ________, _____ & ____.

_______ Fertilizers –________ from chemical compounds _________ and ______ _______ Fertilizers – animal ______, crop residues, bone meal, and compost _______ Fertilizers –________ from chemical compounds ________ – exact ________are _____; they are soluble & thus immediately available to the plant _____– quickly ____ away; this _____ the ______; doesn’t help the water holding capacity of the soil like organic fertilizers do.

____________ Growing plants in _________ _______ suspending plants in water while not using soil Ex. ___________are grown this way. ____________ can ___________ the environment & grow plants where there is no soil; NASA is looking into this. _______ labor-intensive and expensive

SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATION Fertilizers can help _______soil nutrients, but runoff of inorganic fertilizers can cause water ______________. __________ fertilizers: animal manure, plant or green manure or compost. Commercial ___________fertilizers: Active ingredients contain nitrogen, phosphorous, calcium, potassium and other trace nutrients. ______rotation: planting different crops every year to restore nutrients to soil that one crop may take out which next one restores

THE ______ REVOLUTION AND ITS ENVIRONMENTAL IMPACT Since 1950, high-_____ agriculture has produced _____ crops per unit of land. In 1967, fast growing _____varieties of rice and wheat were developed for ______ and ________. Figure 12-7

THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT Lack of _____, high ____ for small farmers, and physical limits to increasing crop yields ______ expansion of the ______ revolution. Since 1978 the amount of ______ land per person has declined due to: Depletion of underground ____ supplies. _________irrigation methods. _____ build-up. _____ of irrigating crops.

THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT Modern ________ has a greater ______ environmental impact than any ______ activity. Loss of a variety of ________ different ____ and ______ strains might limit raw material needed for _____ green and _____ revolutions. E.C. Think GMOs!! What are they? ________________ In the U.S., 97% of the food plant varieties available in the 1940 no longer exist in large quantities.

Biodiversity Loss Soil Air Pollution Human Health Water Loss and degradation of grasslands, forests, and wetlands Erosion Water waste Greenhouse gas emissions from fossil fuel use Nitrates in drinking water Loss of fertility Aquifer depletion Salinization Increased runoff and flooding from cleared land Pesticide residues in drinking water, food, and air Other air pollutants from fossil fuel use Waterlogging Fish kills from pesticide runoff Desertification Sediment pollution from erosion Contamination of drinking and swimming water with disease organisms from livestock wastes Greenhouse gas emissions of nitrous oxide from use of inorganic fertilizers Figure 13.18 Natural capital degradation: major harmful environmental effects of food production. According to a 2002 study by the United Nations, nearly 30% of the world’s cropland has been degraded to some degree by soil erosion, salt buildup, and chemical pollution, and 17% has been seriously degraded. QUESTION: Which item in each of these categories do you think is the most harmful? Fish kills from pesticide runoff Killing wild predators to protect livestock Surface and groundwater pollution from pesticides and fertilizers Loss of genetic diversity of wild crop strains replaced by monoculture strains Belching of the greenhouse gas methane by cattle Bacterial contamination of meat Overfertilization of lakes and rivers from runoff of fertilizers, livestock wastes, and food processing wastes Pollution from pesticide sprays Fig. 12-10, p. 289

THE _______ REVOLUTION To ______ crop yields, we can ___ the _____of similar types of organisms and mix the genes of different organisms. ________selection has been used for centuries to develop genetically improved varieties of crops. Genetic _______develops improved strains at an exponential pace compared to artificial selection. Controversy has arisen over the use of genetically _______ food (GMF/GMOs).

______ _____ Genetic engineering involves ______ a ____ from one species and _______ the DNA into another species. Figure 12-18

PRODUCING MORE _______ About _____ of the world’s ____ is produced by livestock grazing on _____. The other half is produced under ______-like conditions (_______). Densely packed livestock are fed ____ or fish meal. *Why should cows not be feed corn?_________________________ Eating more _____ and farm-raised ____ and less beef and pork ______ harmful environmental ______ of meat production.

Increased meat production Trade-Offs Animal Feedlots Advantages Disadvantages Increased meat production Need large inputs of grain, fish meal, water, and fossil fuels Higher profits Concentrate animal wastes that can pollute water Less land use Reduced overgrazing Figure 13.21 Trade-offs: advantages and disadvantages of animal feedlots. QUESTION: Which single advantage and which single disadvantage do you think are the most important? Reduced soil erosion Antibiotics can increase genetic resistance to microbes in humans Help protect biodiversity Fig. 12-19, p. 295

How Many People can the World Support? Food ________ and ___________ The number of people the world can support depends mostly on their ____ capita ___________ of _____ and _____ and how many _______ couples have. Research has shown that those _____ very ___ on the food chain or very _____ on the food chain ____ ____ _____as ______ as those that live somewhere in between.

PRODUCING MORE MEAT _________ of converting grain into animal protein. Figure 12-13

CATCHING AND RAISING MORE ______ AND ____________ After spectacular increases, the world’s ____ and ____ capita ______ and ________ fish and shellfish catches have _______ off. Figure 12-9

CATCHING AND RAISING MORE FISH AND SHELLFISH Government ________ given to the fishing ________ are a major _____ of _________. Global fishing industry spends about $___ billion per year more than its catch is worth. ________ subsidies many fishing ______would have to go ____ of __________. ____________ allow excess fishing with some keeping their jobs longer with making less money.

__________: Aquatic Feedlots _______ large numbers of ____ and _______ in ponds and cages is world’s fastest growing type of food production. Fish farming involves ________ fish in a ________ environment and ________ them in captivity. Fish ranching involves holding _________ species that live part of their lives in _______ and part in __________. Fish are held for the first few years, released, and then harvested when they return to spawn.

Trade-Offs Aquaculture Advantages Disadvantages High efficiency Needs large inputs of land, feed, and water High yield in small volume of water Large waste output Destroys mangrove forests and estuaries Can reduce overharvesting of conventional fisheries Uses grain to feed some species Figure 13.24 Trade-offs: advantages and disadvantages of aquaculture. QUESTION: Which two advantages and which two disadvantages do you think are the most important? Low fuel use Dense populations vulnerable to disease High profits Tanks too contaminated to use after about 5 years Profits not tied to price of oil Fig. 12-20, p. 296

More Sustainable Aquaculture Solutions More Sustainable Aquaculture • Use less fishmeal feed to reduce depletion of other fish • Improve management of aquaculture wastes • Reduce escape of aquaculture species into the wild • Restrict location of fish farms to reduce loss of mangrove forests and estuaries Figure 13.25 Solutions: ways to make aquaculture more sustainable and reduce its harmful environmental effects. QUESTION: Which two of these solutions do you think are the most important? • Farm some aquaculture species in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean • Certify sustainable forms of aquaculture Fig. 12-32, p. 308

SOLUTIONS: MOVING TOWARD GLOBAL FOOD ___________ People in urban areas could ____ money by _______ more of their ______. ______ gardens provide about ___% of the world’s food supply. Up to ____% of the world’s food is _____.

Solutions: Steps Toward More Sustainable Food Production We can ______ food security by slowing _________ growth, sharply _______ poverty, and slowing ________ degradation of the world’s _____ and ________.